Need to include tax amount in item cost on grpo

Hi all

is there any way where I can book my item cost on grpo basis ??

Well I have one issue, I get material and send for production before creating ap invoice but the cost of my tax not include in item after setting of 100%

non deductible field, and because of this after issue the material when i create ap invoice my tax amount goes in price difference

so is there any way to book tax expenses on grpo ??

Thanks

Ricky